Jinrong Liu

Effect of temperature on the phase behavior and microstructure of aggregates in SDS/Triton X-100/aH2O systems

ABSTRACT The phase behavior and microstructure of a system containing polyoxyethylene tert-octylphenyl (Triton X-100), sodium dodecyl sulfate (SDS) and water were investigated using polarized optical microscopy (POM), differential scanning calorimetry (DSC) and small-angle X-ray diffraction (XRD). Phase-behavior study revealed that lamellar and hexagonal phases occurred in different compositions, and that lyotropic liquid crystal phases tended to form an H phase with increased Triton X-100 content. The effects of temperature on the phase behavior and microstructure of lyotropic liquid crystals were also studied. Heating induced a change from hexagonal to lamellar phase and from gel to hexagonal phase. POM and small-angle X-ray diffraction (SXRD) revealed that the phase-transition temperature of LLCs increased with increased Triton X-100 content, as further supported by DSC data.

Effect of TritonX-100 on the aggregation behavior of SDS in water

ABSTRACT The phase behavior patterns and microstructures of surfactant systems containing sodium dodecyl sulfate (SDS)/TritonX-100/H2O were investigated under a polarizing microscope. Ternary mixtures of SDS/TritonX-100/H2O form two types of well-ordered lyotropic liquid crystals: a hexagonal phase linked to the SDS/water axis and a lamellar phase located at the corner of their phase diagram. Surface tension measurements were conducted for TritonX-100 in the SDS solutions. In the SDS/TritonX-100/H2O system, transition points were found in the surface tension concentration curves at different quality ratios. On the basis of the critical micelle concentration values, the thermodynamic parameters of the aggregate formation, namely, , , and , were estimated. Results show that the addition of TritonX-100 is beneficial to the formation of surfactant aggregates, and thermodynamic data indicate that the micellization of binary mixture of SDS/TritonX-100 in aqueous solution is an entropy-driven spontaneous process. Therefore, the addition of TritonX-100 in SDS aqueous solutions may have potential applications in nanomaterial preparation.